[1S-[1a, 2a(Z), 3a, 4a]]-7-[3-[[[[(1-oxoheptyl)amino]acetyl ]amino]methyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid is a useful cardiovascular agent which can be used, for example, in the treatment of thrombotic disease. A synthesis of this compound is described in U.S. Pat. No. 4,663,336 issued on May 5, 1987. The patent describes a synthesis which is represented by the following scheme. ##STR1##
However, the above process involves the use of hydrazine (NH.sub.2 NH.sub.2) which results in the formation of undesirable side products such as compounds having the formula ##STR2##